Behind theIchthyosaurus platyodon, is placed the restoration of theIchthyosaurus tenuirostris, or Slender-snouted Fish-lizard. The most striking peculiarity of this species is the great length and slenderness of the jaw-bones, which, in combination with the large eye-sockets and flattened cranium, give to the entire skull a form which resembles that of a gigantic snipe or woodcock, with the bill armed with teeth. These weapons, in the present species, are relatively more numerous, smaller, and more sharply pointed than in the foregoing, and indicate that theIchthyosaurus tenuirostrispreyed on a smaller kind of fish. The fore-paddles are larger than the hind ones. In the museum of the Philosophical Institution, at Bristol, there is an almost entire skeleton of the present species which measures thirteen feet in length. It was discovered in the lias of Lyme Regis. Portions of jaws and other parts of the skeletons of larger individuals have been found fossil in the lias near Bristol, at Barrow-on-Soar, in Leicestershire, and at Stratford-on-Avon. TheIchthyosaurus tenuirostrishas also left its remains in the lias formation at Boll and Amburg, in Wirtemberg, Germany.
Of this species, which was the most “common,” when first discovered in 1824, but which has since been surpassed by other species in regard to the known number of individuals, the head is restored, as protruded from the water, to the right of the foregoing species.
TheIchthyosaurus communisis characterised by its relatively large teeth, with expanded, deeply-grooved bases, and round conical furrowed crowns; the upper jaw contains, on each side, from forty to fifty of such teeth. The fore-paddles are three times larger than the hind ones. With respect to the size which it attained, theIchthyosaurus communisseems only to be second to theIchthyosaurus platyodon. In the museum of the Earl of Enniskillen, there is a fossil skull of theIchthyosaurus communiswhich measures, in length, two feet nine inches, indicating an animal of at least twenty feet in length.
The discovery of this genus forms one of the most important additions that geology has made to comparative anatomy. Baron Cuvier deemed “its structure to have been the most singular, and its characters the most monstrous, that had been yet discovered amid the ruins of a former world.” To the head of a lizard it united the teeth of a crocodile, a neck of enormous length, resembling the body of a serpent, a trunk and tail having the proportions of an ordinary quadruped, the ribs of a chameleon, and the paddles of a whale. “Such,” writes Dr. Buckland, “are the strange combinations of form and structure in the Plesiosaurus, a genus, the remains of which, after interment for thousands of years amidst the wreck of millions of extinct inhabitants of the ancient earth, are at length recalled to light by the researches of the geologist, and submitted to our examination, in nearly as perfect a state as the bones of species that are now existing upon the earth.” (Op. cit., vol. v. p. 203).
The first remains of this animal were discovered in the lias of Lyme Regis, about the year 1823, and formed the subject of the paper by the Rev. Mr. Conybeare (now Dean of Llandaff), and Mr. (now Sir Henry) De la Beche, in which the genus was established and named Plesiosaurus (from the Greek words,plesiosandsauros, signifying “near” or “allied to,” and “lizard”), because the authors saw that it was more nearly allied to the lizard than was the Ichthyosaurus from the same formation.
The entire and undisturbed skeletons of several individuals, of different species, have since been discovered, fully confirming the sagacious restorations by the original discoverers of thePlesiosaurus. Of these species three have been selected as the subjects of Mr. Waterhouse Hawkins’s reconstructions and representations of the living form of the strange reptiles.
The first of these has been called, from the relatively larger size of the head, thePlesiosaurus macrocephalus(No. 15), (Gr.macros, long,cephale, head). The entire length of the animal, as indicated by the largest remains, and as given in the restoration, is eighteenfeet, the length of the head being two feet, that of the neck six feet; the greatest girth of the body yields seven feet.
No. 15. Plesiosaurus macrocephalus.
No. 15. Plesiosaurus macrocephalus.
Although Baron Cuvier and Dr. Buckland both rightly allude to the resemblance of the fins or paddles of the Plesiosaur to those of the whale, yet this most remarkable difference must be borne in mind, that, whereas the whale tribe have never more than one pair of fins, the Plesiosaurs have always two pairs, answering to the fore and hind limbs of land quadrupeds; and the fore-pair of fins, corresponding to those in the whale, differed by being more firmly articulated, through the medium of collar-bones (clavicles), and of two other very broad and strong bones (called coracoids), to the trunk (thorax), whereby they were the better enabled to move the animal upon dry land.
Remains of thePlesiosaurus macrocephalushave been discovered in the lias of Lyme Regis, in Dorsetshire, and of Weston, in Somersetshire.
Further to the left, on the shore of the Secondary Island, is a restoration of thePlesiosaurus dolichodeirus, or Long-necked Plesiosaurus (No. 16). The head in this remarkable species is smaller, andthe neck proportionally longer than in thePlesiosaurus macrocephalus. The remains of the Long-necked Plesiosaur have been found chiefly at Lyme Regis, in Dorsetshire. The well known specimen of an almost entire skeleton, formerly in the possession of His Grace the Duke of Buckingham, is now in the British Museum.
The most perfect skeletons of the Plesiosaurus are those that have been wrought out of the lias at Street, near Glastonbury, by Mr. Thomas Hawkins, F.G.S., and which have been purchased by the trustees of the British Museum. A restoration is given by Mr. Waterhouse Hawkins, at No. 17, of a species with characters somewhat intermediate between the Large-headed and Long-necked Plesiosaurs, and which has been called, after its discoverer,Plesiosaurus Hawkinsii.
The Plesiosaurs breathed air like the existing crocodiles and the whale tribe, and appear to have lived in shallow seas and estuaries. That the Long-necked Sea-lizard was aquatic is evident from the form of its paddles; and that it was marine is almost equally so, from the remains with which its fossils are universally associated; that it may have occasionally visited the shore, the resemblance of its extremities to those of a turtle leads us to conjecture; its motion, however, must have been very awkward on land; its long neck must have impeded its progress through the water, presenting a striking contrast to the organisation which so admirably adapted the Ichthyosaurus to cut its swift course through the waves. “May it not, therefore, be concluded that it swam upon, or near the surface,” asks its accomplished discoverer, “arching back its long neck like a swan, and occasionally darting it down at the fish that happened to float within its reach? It may perhaps have lurked in shoal-water along the coast, concealed among the sea-weed, and, raising its nostrils to a level with the surface from a considerable depth, may have found a secure retreat from the assaults of dangerous enemies; while the length and flexibility of its neck may have compensated for the want of strength in its jaws, and its incapacity for swift motion through the water, by the suddennessand agility of the attack which enabled it to make on every animal fitted for its prey which came within its reach.”[5]
For the Secondary Island three species of the Plesiosaurus have been restored, thePlesiosaurus macrocephalus, thePlesiosaurus dolichodeirus(Gr.dolichos, long,deire, neck), and thePlesiosaurus Hawkinsii. The name “long-necked” was given to the second of these species before it was known that many other species with long and slender necks had existed in the seas of the same ancient period: the third species is named after Mr. Thomas Hawkins, F.G.S., the gentleman by whose patience, zeal, and skill, the British Museum has been enriched with so many entire skeletons of these most extraordinary extinct sea-lizards.
The remains of all these species occur in the lias at Lyme Regis, and at Street, near Glastonbury; but thePlesiosaurus Hawkinsiiis the most abundant in the latter locality.
{uncaptioned}
“Trias” is an arbitrary term applied in geology to the upper division of a vast series of red loams, shales, and sandstones, interposed between the lias and the coal, in the midland and western counties of England. This series is collectively called the “New Red Sandstone formation,” to distinguish it from the “Old Red Sandstone formation,” of similar or identical mineral character, which lies immediately beneath the coal.
The animals which have been restored and placed on the lowest formation of the Secondary Island, are peculiar to the “triassic,” or upper division of the “New Red Sandstone” series, which division consists, in England, of saliferous (salt-including) shales and sandstones, from 1000 to 1500 feet thick in Lancashire and Cheshire, answering to the formation called “Keuper-sandstone” by the German geologists; and of sandstone and quartzose conglomerate of 600 feet in thickness, answering to the German “Bunter-sandstone.”
The largest and most characteristic animals of the trias are reptiles of the order
The name of this order is from the Greek wordbatrachos, signifying a frog: and the order is represented in the present animal-population of England by a few diminutive species of frogs, toads, and newts, or water-salamanders. But, at the period of the deposition of the new red sandstone, in the present counties of Warwick and Cheshire, the shores of the ancient sea, which were then formed by that sandy deposit, were trodden by reptiles, having the essential bony characters of the Batrachia, but combining these with other bony characters of crocodiles and lizards; and exhibiting both under a bulk which is made manifest by the restoration of the largest known species, (No. 16), occupying theextreme promontory of the Island, illustrative of the lowest and oldest deposits of the secondary series of rocks. The species in question is called the—
or the Salamander-like Labyrinthodon; the latter term being from the Greek, signifying the peculiar structure of the teeth, which differ from all other reptiles in the huge Batrachia in question, by reason of the complex labyrinthic interblending of the different substances composing the teeth. The skull of the Labyrinthodon is attached to the neck-bones by two joints or condyles, and the teeth are situated both on the proper jaw-bones, and on the bone of the roof of the mouth called “vomer:” both these characters are only found at the present day in the frogs and salamanders. The hind-foot of the Labyrinthodon was also, as in the toad and frog, much larger than the fore-foot; and the innermost digit in both was short and turned in, like a thumb.
No. 18. Labyrinthodon Salamandroides.
No. 18. Labyrinthodon Salamandroides.
Consecutive impressions of the prints of these feet have been traced for many steps in succession (as is accurately represented inthe new red sandstone part of the Secondary Island) in quarries of that formation in Warwickshire, Cheshire, and also in Lancashire, more especially at a quarry of a whitish quartzose sandstone at Storton Hill, a few miles from Liverpool. The foot-marks are partly concave and partly in relief; the former are seen upon the upper surface of the sandstone slabs, but those in relief are only upon the lower surfaces, being, in fact, natural casts, formed on the subjacent foot-prints as in moulds. The impressions of the hind-foot are generally eight inches in length and five inches in width: near each large footstep, and at a regular distance—about an inch and a half—before it, a smaller print of the fore-foot, four inches long and three inches wide, occurs. The footsteps follow each other in pairs, each pair in the same line, at intervals of about fourteen inches from pair to pair. The large as well as the small steps show the thumb-like toe alternately on the right and left side, each step making a print of five toes.
Foot-prints of corresponding form but of smaller size have been discovered in the quarry at Storton Hill, imprinted on five thin beds of clay, lying one upon another in the same quarry, and separated by beds of sandstone. From the lower surface of the sandstone layers, the solid casts of each impression project in high relief, and afford models of the feet, toes, and claws of the animals which trod on the clay.
Similar foot-prints were first observed in Saxony, at the village of Hessberg, near Hillburghausen, in several quarries of a gray quartzose sandstone, alternating with beds of red sandstone, and of the same geological age as the sandstones of England that had been trodden by the same strange animal. The German geologist, who first described them, proposed the name ofCheirotherium(Gr.cheir, the hand,therion, beast), for the great unknown animal that had left the foot-prints, in consequence of the resemblance, both of the fore and hind feet, to the impression of a human hand, and Dr. Kaup conjectured that the animal might be a large species of the opossum-kind. The discovery, however, of fossil skulls, jaws, teeth, and a few other bones in the sandstones exhibiting the footprints in question, has rendered it more probable that both the footprints and the fossils are evidences of the same kind of huge extinct Batrachian reptiles.
An entire skull of the largest species discovered in the new red sandstones of Wurtemberg; a lower jaw of the same species found in the same formation in Warwickshire; some vertebræ, and a few fragments of bones of the limbs, have served, with the indications of size and shape of the trunk of the animal yielded by the series of consecutive foot-prints, as the basis of the restoration of theLabyrinthodon salamandroides, in the Secondary Island. It is to be understood, however, that, with the exception of the head, the form of the animal is necessarily more or less conjectural.
This name, signifying the Thick-jawed Labyrinthodon, was given by its discoverer to a species of these singular Batrachia, found in the new red sandstone of Warwickshire, and which bears to the largest species the proportion exhibited by the head and fore-part of the body, as emerging from the water, for which parts alone the fossils hitherto discovered justify the restoration.[6]
Nos. 19 & 20. Section of Tooth of Labyrinthodon.aPulp-cavity:b binflected folds of ossified capsule of tooth.
Nos. 19 & 20. Section of Tooth of Labyrinthodon.aPulp-cavity:b binflected folds of ossified capsule of tooth.
In 1844 Mr. Andrew G. Bain, who had been employed in the construction of military roads in the colony of the Cape of Good Hope, discovered, in the tract of country extending northwards from the county of Albany, about 450 miles east of Cape Town, several nodules or lumps of a kind of sandstone, which, when broken, displayed, in most instances, evidences of fossil bones, and usually of a skull with two large projecting teeth. Accordingly, these evidences of ancient animal life in South Africa were first notified to English geologists by Mr. Bain under the name of “Bidentals;” and the specimens transmitted by him were submittedat his request to Professor Owen for examination. The results of the comparisons thereupon instituted went to show that there had formerly existed in South Africa, and from geological evidence, probably, in a great salt-water lake or inland sea, since converted into dry land, a race of reptilian animals presenting in the construction of their skull characters of the crocodile, the tortoise, and the lizard, coupled with the presence of a pair of huge sharp-pointed tusks, growing downwards, one from each side of the upper jaw, like the tusks of the mammalian morse or walrus. No other kind of teeth were developed in these singular animals: the lower jaw was armed, as in the tortoise, by a trenchant sheath of horn. Some bones of the back, or vertebræ, by the hollowness of the co-adapted articular surfaces, indicate these reptiles to have been good swimmers, and probably to have habitually existed in water; but the construction of the bony passages of the nostrils proves that they must have come to the surface to breathe air.
Some extinct plants allied to the Lepidodendron, with other fossils, render it probable that the sandstones containing the Dicynodont reptiles were of the same geological age as those that have revealed the remains of the Labyrinthodonts in Europe.
The generic name Dicynodon is from the Greek words signifying “two tusks or canine teeth.” Three species of this genus have been demonstrated from the fossils transmitted by Mr. Bain.
TheDicynodon lacerticeps, or Lizard-headed Dicynodon, attained the bulk of a walrus; the form of the head and tusks is correctly given in the restoration (No. 21); the trunk has been added conjecturally, to illustrate the strange combination of characters manifested in the head.
A second species, with a head so formed as to have given the animal somewhat of the physiognomy of an owl, has been partially restored at No. 22.
No. 8. Dinornis.
No. 8. Dinornis.
[1]Lyell, “Manual of Elementary Geology.”[2]“The first specimens of the teeth were found by Mrs. Mantell in the coarse conglomerate of the Forest, in the spring of 1822.”—Mantell, “Geology of the South-East of England,” 8vo, 1833, p. 268.[3]“Report of British Fossil Reptiles,” 1841, p. 110.[4]Op. cit., p. 174.[5]“Transactions of the Geological Society,” Second Series, vi. 503. 1841.[6]Conybeare, Geol. Trans., i. 388.
[1]Lyell, “Manual of Elementary Geology.”
[2]“The first specimens of the teeth were found by Mrs. Mantell in the coarse conglomerate of the Forest, in the spring of 1822.”—Mantell, “Geology of the South-East of England,” 8vo, 1833, p. 268.
[3]“Report of British Fossil Reptiles,” 1841, p. 110.
[4]Op. cit., p. 174.
[5]“Transactions of the Geological Society,” Second Series, vi. 503. 1841.
[6]Conybeare, Geol. Trans., i. 388.
BRADBURY AND EVANS, PRINTERS, WHITEFRIARS.